For technical discussions about electricity, electrical equipment with particular emphasis on safe and compliant installations.
Off topic remarks are liable to be moved elsewhere, or in extreme cases to be deleted.
Low electricity demand in the summer could present a challenge to managing the electricity system, system operator NGESO said in its weekly Covid-19 briefing.
The balance of supply and demand in the summer has been a growing problem over recent years, as demand is much lower and may be served by onsite capacity such as rooftop PV, while generation from solar PV and other ‘must run’ renewables has increased.
It means that ‘dispatchable’ plant that would otherwise be asked to flex up and down to help manage inertia, voltage, etc, are not in use. The problem is made more acute because voltage has to be managed locally, so NGESO needs access to a variety of plant across the country.
That issue is likely to be exacerbated if Covid-19 measures continue to reduce electricity demand.
Low electricity demand in the summer could present a challenge to managing the electricity system, system operator NGESO said in its weekly Covid-19 briefing.
The balance of supply and demand in the summer has been a growing problem over recent years, as demand is much lower and may be served by onsite capacity such as rooftop PV, while generation from solar PV and other ‘must run’ renewables has increased.
It means that ‘dispatchable’ plant that would otherwise be asked to flex up and down to help manage inertia, voltage, etc, are not in use. The problem is made more acute because voltage has to be managed locally, so NGESO needs access to a variety of plant across the country.
That issue is likely to be exacerbated if Covid-19 measures continue to reduce electricity demand.
Having too much generating capacity that has to be throttled and managed is a much easier problem then not having enough to meet demand. We should all have such problems especially with cash income.
I heard that the "ride through" settings were what was behind the South Australia blackout a few years ago. From experience in the Australian and NZ power system but not the UK I understand that the under and over voltage and frequency settings are what is changed.
Making hydrogen is an interesting possibility and is being looked at in Australia. It would possibly make sense short term to make hydrogen during periods of excess electricity generation and inject it in the gas grid. Given the losses in electrolysis and "fuel cell" process to make electricity from hydrogen I don't think it makes good sense to use hydrogen as a medium to store electrical energy. I understand the round trip efficiency is about 40% compared with pumped hydro being about 70% efficient.
Having too little synchronous inertia - not talked about in this report - will also become an issue with excess renewable generation.
Under present or near future conditions, hydrogen production is most unlikely to be viable.
Bulk hydrogen production involves a lot of expensive plant and equipment, with appreciable fixed costs even when not being used.
Building such plant is unlikely to be viable if it is only used for a few dozen hours a year when there is an electricity surplus.
What is needed is cheap and simple ways to encourage extra electricity consumption, but only at times of surplus.
Several ways exist to do this.
1) Install bulk electric water heaters in premises that usually burn gas for water heating. Under remote control such that gas is used normally, but with changeover to electricity when this is cheaper than gas.
2) Bulk frozen food stores are often kept at about minus 20 degrees. Install remote means to drop this to say minus 25 degrees at times of electricity surplus. The surplus is thereby in effect stored as "cold"
3) Large scale air conditioning, can be fitted with buffer tanks containing a very dilute anti freeze solution, this is frozen at times of electricity surplus thereby also storing "cold" for later use.
4) Greater use of electric vehicles, charging of same at times of surplus being encouraged by preferential tariffs.
"Installers and owners of emergency diesels must assume that they will have to run for a week or more"
adam2 wrote:Under present or near future conditions, hydrogen production is most unlikely to be viable.
Bulk hydrogen production involves a lot of expensive plant and equipment, with appreciable fixed costs even when not being used.
Building such plant is unlikely to be viable if it is only used for a few dozen hours a year when there is an electricity surplus.
What is needed is cheap and simple ways to encourage extra electricity consumption, but only at times of surplus.
Several ways exist to do this.
1) Install bulk electric water heaters in premises that usually burn gas for water heating. Under remote control such that gas is used normally, but with changeover to electricity when this is cheaper than gas.
2) Bulk frozen food stores are often kept at about minus 20 degrees. Install remote means to drop this to say minus 25 degrees at times of electricity surplus. The surplus is thereby in effect stored as "cold"
3) Large scale air conditioning, can be fitted with buffer tanks containing a very dilute anti freeze solution, this is frozen at times of electricity surplus thereby also storing "cold" for later use.
4) Greater use of electric vehicles, charging of same at times of surplus being encouraged by preferential tariffs.
I would say that your number four has the greatest chance of being widely adopted.
vtsnowedin wrote:You can not generate hydrogen as it is an element. You can separate it from water or from natural gas but not generate it.
Apologies.
What I meant was generate hydrogen from H2O preferably. I rather assumed that people here would understand that. But given the number of visitors that we get perhaps I should have made it plainer for clarity. Thank you for bringing it up, VT.
Most hydrogen is generated at the moment from natural gas which is not a very environmental way of doing it as the process has an unwanted bi-product, CO2. Natural gas being methane, CH4 produces mainly hydrogen but it does leave a significant amount carbon which eventually goes atmosphere as CO2.
Using water as a source leaves oxygen as a bi-product which is then recombined with the hydrogen when the hydrogen is burned so it is a closed cycle with the only waste product being the energy used to split the water molecule in the first place and some heat losses.
vtsnowedin wrote:You can not generate hydrogen as it is an element. You can separate it from water or from natural gas but not generate it.
Apologies.
What I meant was generate hydrogen from H2O preferably. I rather assumed that people here would understand that. But given the number of visitors that we get perhaps I should have made it plainer for clarity. Thank you for bringing it up, VT.
Most hydrogen is generated at the moment from natural gas which is not a very environmental way of doing it as the process has an unwanted bi-product, CO2. Natural gas being methane, CH4 produces mainly hydrogen but it does leave a significant amount carbon which eventually goes atmosphere as CO2.
Using water as a source leaves oxygen as a bi-product which is then recombined with the hydrogen when the hydrogen is burned so it is a closed cycle with the only waste product being the energy used to split the water molecule in the first place and some heat losses.
Yes to all of that and I knew what you meant to say but so many people read stuff on the internet and take it as gospel without any critical thinking. If you had said "separate hydrogen from water by electrolysis" instead of" generate" it would have been wordy but accurate for readers not up to speed on the science.
Also it is day thirty for me of social distancing and I'm becoming a bit of a nit picker among other evils. Please bare with me.
Yes, i'm one of those on this tariff. Last Sunday was the first time in 2 years of Octopus running this tariff that the price has gone negative during the day time (negative pricing happens periodically but always overnight to date).
Prices were negative between 1030 and 1600. Down to approx -4p per kWh.
The proceeding nightime was also very cheap with prices in the 1-2p per kWh range.
Normal day time prices during this working week have been 5-8p/kWp; prices jump between 4pm and 7pm and then back down again.
Total demand has fallen, but daytime use has increased.
"Households are consuming 21% less electricity than usual at 07:30, as fewer people commute to work, and are taking back the time to sleep later instead," a spokeswoman for Bulb Energy said, based on data from more than 2,000 smart meters.
Having taken back this time they may be reluctant to have it taken
away again.
