“The Scottish Government’s targets are for renewable sources to generate the equivalent of 100 per cent of Scotland’s gross annual electricity consumption by 2020.” What will the consequences be for the Scottish People?
This post models Scottish electricity production and consumption in 2020 and compares this with 2012. It is assumed that Scotland’s two nuclear power stations remain operational in 2020. The reader is asked to always recall that the numbers are based on models and the conclusions therefore carry uncertainty. The consequences of this energy policy may be:
- A large electricity surplus of about 15 TWh may be produced in 2020, worth about £2.5 billion at 17p / KWh.
- There are currently many ideas but no certainty about where this surplus might go. It seems possible that a large part may simply be wasted.
- Assuming that marine renewables remain negligible and hydro output remains unchanged in 2020 then the bulk of the expansion in renewables to meet the target will most likely be met by wind that will require a 5 fold increase relative to 2012.
- In an independent Scotland the subsidy payments currently made to renewables companies by 63 million UK citizens would fall pro rata on the shoulders of 5.3 million Scottish citizens. This, combined with the 5 fold increase in wind capacity may mean a 25 fold increase in the level of renewable subsidy born by Scottish electricity consumers. Electricity bills may double.
In summary, the Scottish Government energy plan may result in a large electricity surplus that at present has nowhere to go, the number of wind turbines may increase 5 fold and electricity bills may double.
Figure 1 Scottish renewable electricity growth according to Scottish Government data . It has proven difficult to reconcile exactly the Scottish Government data with DECC data and BM reports / Gridwatch. Electricity produced from landfill gas and biofuels are not included in the models presented here. It is clear that the vast majority of the growth in recent years has come form wind. Hydro periodically suffers from low rainfall.
On 18 September this year, Scotland will vote on whether or not it will remain a part of the United Kingdom. The current Scottish majority government with the Scottish National Party (SNP) at the helm has the energy policy detailed above and below. It is well on its way to being implemented at a cost of billions of pounds. While this post is focussed on Scotland, the lessons and implications may apply to any country going down the high renewable route.
This parliamentary committee report  makes clear the Scottish Government (SNP) electricity energy policy (in section 46):
46. The Scottish Government’s targets are for renewable sources to generate the equivalent of 100 per cent of Scotland’s gross annual electricity consumption by 2020. A target has also been set for renewable sources to provide the equivalent of 11 per cent of Scotland’s heat demand by 2020. Within the electricity generation target, a target has been set for “local and community ownership of 500 MW electricity by 2020”.
It is the first part of this target that is the subject of this post, “to generate 100% of Scotland’s gross annual electricity consumption from renewable sources by 2020” – less than 6 years from now. This policy is nuanced. Not 100% of electricity consumed but the equivalent of 100% of gross annual electricity consumed allowing important wriggle room for other sources to enter the mix.
The Electricity Generation Models
I am not aware of detailed electricity generation statistics for Scotland. I have therefore used the UK power stations capacity data base published by DECC  that was last updated to the end of May 2013 and UK generation data from BM reports as recorded by Gridwatch  and allocated generation to Scotland on a pro rata basis from the UK statistics. I compare a model for 2012 with a future model for 2020 where 100% of Scotland’s gross electricity consumption comes from the renewable sources of hydroelectric and wind power. This approach is imperfect but should not significantly alter the main conclusions.
I have plotted full year generation data for 2012 as downloaded from Gridwatch. The data are recorded with 5 minute resolution resulting in over 150,000 lines of data for a full year which has pushed my Mac and XL to their limits. Click on all charts to get a LARGE version that will open in a new browser window. Save to your HD and open in your graphics viewing application – on a Mac that is Preview. Zoom in for details. I have had to reduce the resolution of these large charts to upload to WordPress.
Scottish Power Generating Assets
In 2012, Scotland had the following power generating assets  (Figure 2):
- Torness nuclear 1185 MW
- Hunterstone B nuclear 890 MW
- Longannet coal 2400 MW
- Peterhead CCGT 1180 MW
- Hydro suit 1602 MW
- Wind park 3813 MW
- Total capacity 11070 MW
- Peak demand 5900 MW
Thus capacity is greatly in excess of demand and the addition of 3813 MW of wind (and growing fast) has exacerbated the oversupply situation. Scotland has historically been a significant exporter of power to England. In this analysis I have ignored an array of smaller power generators such as biomass (Steven’s croft) and poultry litter (Westfield).
Figure 2 Map (somewhat outdated) of the main generating assets and grid in Scotland and N England. Power stations like Cockenzie and Methil are already closed. 
2012 Scottish Electricity Generation Model
The 2012 generating model is shown in Figure 3. Nuclear supply is based on [(Scottish capacity / UK capacity) * UK nuclear generation]. Hydro and wind are prorated in the same way. Demand is prorated with Scotland = 10.34% of UK demand. The difference between demand and the combined nuclear + hydro + wind supply is that which has to be met from other sources (coal and gas) or from imports as shown in Figure 4.
Figure 3 Click chart for large version. In 2012, nuclear+hydro+wind did not produce sufficient power to satisfy demand. The deficit (Figure 3) was largely met from Longannet and Peterhead.
Figure 4 Click chart for large version. This chart shows demand less nuclear+hydro+wind, which is the load met by Longannet and Peterhead. Note how on a few occasions, Scotland was fossil fuel generation free, especially during the windy Christmas holiday season at the end of the year.
Figure 4 shows occasional surpluses which occur mainly on windy nights (see Figure 3). But the pattern is one of fluctuating deficit normally below 2000 MW but occasionally approaching 4000 MW in winter. In 2012 this deficit will have been met mainly from coal and gas capacity that totals 3580 MW, some pumped hydro, smaller generators and imports from England.
If you zoom in on Figure 3 you will see that the pattern of deficit that needed to be balanced in 2012 is dominated by and following demand. With this configuration, the load balancing task has not been much altered with the addition of wind that had an annual total of 17% penetration.
2020 Scottish Electricity Generating Model
Scotland’s two nuclear power stations are not due to close until 2023 and so it is assumed they remain operational in 2020, although the SNP policy is effectively for a nuclear free Scotland once these power stations close.
In the 2020 model, nuclear and hydro generation have been kept the same as in 2012 as has demand (Figure 5). Wind has been scaled up so that wind + hydro (renewables) equals total annual demand. It is assumed that marine renewables will remain negligible in 6 years time. Note that Y-axis scale has been increased to accommodate peak supply that on occasions exceeds 12000 MW. The pattern of surplus and deficit is shown in Figure 6.
Figure 5 Click chart to enlarge. The parameters of this chart are the same as shown in Figure 3 apart from wind has been scaled so that wind+hydro = annualised total demand. It is clear that low carbon energy sources now meet demand for most of the time with large electricity surpluses for most of the time that are plotted in Figure 6. Note that hydro load is simply that copied from 2012. In the new environment with excess wind power hydro may be used to part balance the system and eliminate some of the periodic deficits (Figure 6).
Figure 6 Click chart to enlarge. In 2020, the model shows that Scotland is almost running a continuous electricity surplus. The small deficits may be reduced further by managing hydro production to span lulls and by the addition of more pumped hydro. There does not appear to be an issue with power security, apart from the affordability of this set up. The surpluses on occasions exceed 8000 MW, greatly in excess of the current inter connector capacity between Scotland and England. It seems possible that one of the nuclear power plants (Huntertsone B) might close in 2023 and that will absorb some of this surplus.
In Figure 5 there is a total of 29.7 TWh of wind and 3.0 TWh of hydro to satisfy 32.7 TWh of demand satisfying the call for gross 100% renewables production. Wind generation in 2012 was modelled at 5.7 TWh and the model therefore calls for over a 5 fold uplift in wind capacity in 2020 relative to 2012. If you don’t have a wind farm on your door step yet, you had better watch out.
Figure 5 shows that despite the gigantic uplift in wind capacity there are still numerous spells of electricity deficit that may be managed in part by adjusting hydro load. The remaining deficit may be met by the CCGT at Peterhead and imports from England. As discussed below, it does not seem likely that Longannet Powerstation can stay open. Peterhead CCGT is about to be “upgraded” to a carbon capture and storage demonstration plant . I don’t really know how this is going to work! Peterhead will presumably need to run 24/7 to warrant the investment in CCS making the surplus even greater.
There are a number of consequences that flow from this modelling exercise that deserve scrutiny.
Where will the surplus go?
The net surplus represents 14.8 TWh of electricity which priced at £0.17 per KWh is worth £2.5 billion. At present the only place for such a surplus to go is England but we do not currently have the connection capacity to export, on occasions, over 8000 MW. A major question is whether or not England would need to or want to import this stochastic power? It must be born in mind that times of surplus wind in Scotland are often times of surplus in England too. England may take some as it suits them but unlikely a significant amount.
Interconnection with other European countries is another option often discussed, especially Norway. This model would involve Norway importing cheap electricity from Scotland on availability and exporting expensive electricity to the continent on demand. There would be little need for Scotland to import from Norway unless this was to satisfy demand in England.
Storage is another option and pumped hydro storage offers good energy efficiency. Scotland does not as yet have significant pumped storage capacity but there are plans to build a new large facility in Coire Glas that would have 30 GWh capacity . The 14.8 TWh surplus is sufficient to fill Coire Glas 493 times. With 600 MW generating capacity, Coire Glas could meet much of the deficit (Figure 4) but with only about 37 deficit events the demand for pumped storage in Scotland is much smaller than the gigantic surplus could fill.
The Scottish Government and Aberdeen local government have long been keen on hydrogen as a means of storing surplus wind power. I too was keen on this idea for a while many years ago until I learned about energy efficiency. If hydrogen is made by electrolysis of water and used in a fuel cell to power a car or bus then there are huge energy losses along the way that I once estimated to be 76% of the energy supplied . In other words, going this route would mean wasting 11.3 TWh of the surplus or £1.9 billion.
Should Scotland fail to find an export market or to develop large scale storage, both of which seem likely, then the only other option will be to spill the electricity or to curtail generation. The landscape will be plastered with turbines, the population sadelled with enormous costs (see below) for little to no benefit.
Where I stay in Aberdeen I am not immediately affected by the landscape impact of wind farms. But drive out of the city into the counties of Aberdeenshire or Angus and wind farms are everywhere. They are on every mountain ridge and hill top. While some of the future wind capacity may be built offshore, though this is also controversial , Scots and the important tourist industry should be prepared for things to get approximately 4 times as bad (factored down from 5) as they were in 2012.
One casualty of the massive expansion of wind power will have to be Longannet coal fired power station which I imagine will close before 2020. The plan is, after all, to get rid of fossil fuel powered generation even although coal is likely to be the cheapest form of power production for many decades.
Scotch on the ROCs
Renewable Obligation Certificates or ROCs are the consumer paid subsidies to the renewable energy producers. In 2012, Scotland had 44% of UK wind capacity. The ROCs payable were met by the whole UK population of 63 million. With independence it seems likely that 5.3 million Scottish consumers will have to pay the subsidies on electricity generated in Scotland. That would imply a 5.2 fold uplift in the per capita level of subsidy payments on 2012 levels of production (63/5.3*44%). Come 2020, the energy plan calls for a 5 fold uplift in wind capacity and that would hence result in a 25 fold uplift in the per capita subsidy payments in 2020 relative to 2012.
Wikipedia suggests that the cost of a ROC in 2012 was roughly 0.5p per KWh. In essence, an independent Scotland may have to service 25 times as many ROCs as today (many more KWh of renewable power) that needs to be compared with electricity price of about 17p / KWh. Scottish electricity prices could be set to double.
The SNP have said they want the single electricity market to continue along with the single currency and you can see why. I cannot think of a single reason why English consumers would want to pay subsidies to Scottish renewable electricity producers should Scotland elect to go it alone. This seems like a recipe for disaster and the details of this certainly need to be clarified before the vote. I don’t see any way that Scottish domestic and commercial consumers could bear such a burden and one possible unintended consequence of a yes vote might therefore be the abolition of ROCs and the collapse of the energy plan.
 DECC map of UK powerstationsmap
 Energy Matters: The Coire Glas pumped storage scheme – a massive but puny beast
 The Oil Drum: The energy efficiency of cars
Disclaimer: This is a technically complex post where some far reaching conclusions are reached based on extrapolation from UK data into the Scottish domain. If I have made any gross errors then please bring these to may attention in comments and I will endeavour to correct or highlight them.