Diesel isn’t the answer to intermittent electricity supply

Scott Petersen

Ironically, the drive for sustainability is promoting electricity generation that is far from green

In the electricity market, there have been several narrow squeaks this winter period, when National Grid ESO (NGESO) has had to issue Electricity Margin Notices (EMNs). EMNs are a kind of amber-flag warning that occur when the operating margin, or spare capacity in our electricity system is threatened. Recently, when seasonal demand has been high, generation supply from renewable wind and solar sources has dropped away as a result of the wrong kind of weather, and NGESO has been forced to take corrective action to avert a potential crisis.

At the root of the problem is the UK’s switch from fossil fuels to renewable energy production, which in turn is being driven by our commitment to achieving a national, legal, Net Zero target by 2050. We are now witnessing the downside to this energy strategy in the shape of intermittent electricity supply which is resulting in these regular EMN occurrences.

One way that NGESO can respond in these tight situations, is to seek a solution through the balancing markets, to bridge the potential shortfall in supply and to avoid power cuts. The EMNs issued by NGESO are a signal to alternative energy providers to respond to the situation by providing additional reserves to ensure there is a healthy safety buffer, thus ensuring that the margin never reaches the point where it is compromised. This technique is referred to as Demand Side Response, or DSR.

Unfortunately, in these critical periods of supply shortage, a large proportion of the additional supply that NGESO is forced to rely on is fossil-fuel based. It comes in the form of traditional coal and small gas-fired generation, but also comes from diesel farms (banks of diesel generators) and back-up power generators, fired up for short periods. Oil and diesel still represented 9% o the electricity generation mix in 2019 and when located in urban areas (which many back-up generators are), they can be noisy and produce hazardous quantities of particulates. Ironically, the diesel generators are greater polluters that the problem they are trying to solve.
Even worse, our friends at NGESO are walking a tightrope at these critical times and are often forced to pay these DSR operators outrageous prices at several times the normal rate, to bail us out and maintain normal service across the grid.

Fortunately, there are other, more sustainable sources of DSR. Batteries are becoming an increasingly viable alternative, storing energy at off-peak times and feeding it back during a DSR event.

Then, there is the DSR which OakTree Power is pioneering which targets consumption reduction. This type of DSR is clean, silent, simple and inexpensive to set up, and helps NGESO by addressing the demand end of the equation, thus reducing the need to produce more electricity. You might be surprised to learn that this technology has been around for some time, but until now has only been the domain of large energy consumers, like smelting works, paper mills and large manufacturing plants. Now for the first time, OakTree Power, acting as an “aggregator”, can make DSR a reality for hundreds of organisations with medium to large commercial buildings.

It’s all done by tapping into a building’s ability to adjust its electricity demand at Peak Times and triggering a DSR event that fine-tunes electricity consumption down a small amount, for a short period of time, when critical power fluctuations occur on the grid. That cumulatively creates significant energy and CO2 emissions reductions.

Taking all the buildings across London with a footprint of greater than a 50,000 sq. ft., we estimate DSR could work successfully for over 1,500 organisations and save around 26,000 tonnes of CO2 per annum. That’s the equivalent of taking a small, gas-fired power station offline, or removing 7,500 commuter cars from our roads. It would also means reducing our reliance on the dirty diesel generators that fire up as part of DSR to meet the shortfall.

So, let’s make a clean start by helping NGESO do its job and the UK to tackle its climate-change targets, through implementing the clean-type of DSR more widely.