Super cold in Dallas with many cloudy days

dallas, tx cold

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On Monday the 15th of February 2021 Texas is experiencing record electric demand while struggling with some loss of power from both renewable and non renewable sources.  Many people have seen their power shut off sometimes for hours.  While some maintain that we are headed for warmer weather in winter and summer this record breaking cold spell that grips much of the US shows that simplification of the complex climate system is foolish.  What would be the situation if we were dependent on solar power for much of our electricity?  After a number of cloudy days no reasonable amount of batteries would have any charge and today with some sun the panels would have to be cleared of snow to be able to generate a few hours of power at a small fraction of their rated capacity.  We must get real about energy and its use.  Times like this with extremely low temperatures make clear that we need to build more well insulated buildings with less glass.  Building designers don’t really prioritize energy efficiency in so many cases.  In normal winter weather here in Dallas the heat is barely needed and a south facing window may pickup more heat than it gives off but on a very cold cloudy day that big window is a huge energy thief chilling the space.
 
Many advocated for the use of electric heat pumps as a better alternative to natural gas heating.  In fact some areas are banning new natural gas hookups for home.  Some builders are building homes in the outer areas of Dallas where there isn’t natural gas piping and choosing to save money developing the lots by not paying to bring it in.  My engineer lives in a nice home outside Dallas that doesn’t have sewer or natural gas in a subdivision that was built with big lots that allow micro-sewer systems to be installed at each home that use the treated waste water to irrigate a small part of the back yard.  Heat pumps work as an air conditioner in reverse cooling the outdoors and directing the heat from condensing the refrigerant into the house.  As is well known such systems move more heat by far than the electrical energy that powers them when the climate conditions are warm enough to allow the evaporation of the refrigerant to cool the outside air.  The problem comes when the outside air is colder than the evaporation temperature, then the refrigerant remains liquid and the system stops moving heat.  Heat pump designers deal with this by installing much less efficient electric resistance heating coils in the inside air handler to take over when the temperature is too low for the much more efficient heat pump to work.  That is what is happening today when the temperature is at record lows.  Luckily a large amount of the heating in Texas is done by natural gas or propane which doesn’t face a huge increase in energy use when the temperature drops low other than the increased heat load of the house.  With an electric heat pump there is a double hit of increased need for heating and a sharply lower efficiency of the system.
 
Texas has a lot of wind power but the news today said that some are frozen so that further cuts the power supply.  Luckily my house so far as not had a power outage but when I came to my office today thru the snow a number of red lights were out indicating blackouts and while my power was luckily back on at my office it had gone out during the night.  Sadly with the large amount of wind power that has been constructed and solar promoters building new solar farms the market for a natural gas power plant has shrunk and is losing favor as a badly needed backup of unreliable renewable power. 
Texas has an auction market for electricity in which prices fluctuate wildly depending on weather, time of day and availability of power sources.  The state grid operator just chooses the lowest price power provider at any time which means that at night when the always on coal and nuclear plants are competing with usually abundant wind power that is strongest at night the rates in normal times can drop near zero.  But last night with record cold and some of the wind turbines frozen there was a shortage of power and up to a million Texans lost their power.  My stepson spend the night at a friends where the power went off and the house was 40 degrees in the morning!!! 
 
Investors in something like a quick acting natural gas power plant called a peaker face uncertain income and the myth that cheap battery storage is coming to provide extra power like they really do.  People look at the long term when investing and why invest in a needed natural gas plant if miracle batteries are going to make them obsolete!!  Much is made of big battery installations which have come down in price which are usually rated in terms of how many homes they can power for two hours.  Battery proponents see batteries as being able to soak up excess renewable energy such as solar at mid day and emit it when the solar power is gone in the late afternoon and on an ideal day that can work for some of the time.  No one talks about what to do on a week like last week with days of cold cloudy weather where there is no solar power for many days.  Battery materials are limited and costs will increase with more demand.  There are proposals to build some limited battery storage but these are intended for short duration power delivery with recharges twice a day to meet peak power demand in the morning and evening when solar doesn’t make power.  There is not anything like the amount of battery backup needed for more than a fraction of the needed power during those short spells.  In practice if we are realistic about solar power every megawatt of solar should be backed up by a megawatt of natural gas peaker power plant that can quickly step in during all the time when solar is offline including for days of cloudy weather like last week.
 
WE need to get real about solar energy capability which the industry hates to be truthful about.  They love to talk about rated capacity which is the electric output at an optimal 1000 watts of solar radiation per square meter.  They use that benchmark to talk about how cheap solar power is when you divide the rated capacity by the installed cost being very optimistic about received solar radiation and other factors.  What they don’t like to talk about is how short the time of power production actually is and how in a city like Dallas the actual solar radiation on a typical winter week could look like this.
Now it maybe hard for you to read the numbers on the graph but the good days peaks for a short time at just 500 watts per square meter for such a short time as to make it impossible to charge a battery.  The three cloudy days mark solar radiation so low as to not make significant power.  This week is far better than last week was but would be a disaster if you were relying on a very optimistic ideal of solar power and short term battery backup.  We need to get real and take action to make sure that we have reliable power especially on days like today when indoor temperatures can drop dramatically if the power goes out.
 
Solar in the winter really can’t deliver more than a fraction of the summer power but if we have natural gas power plants sized to provide more than enough power to back it up we can get some use out of solar on sunny winter days even if they are only a day or two a week.    Now there is another problem and that is a failure to have extra natural gas available with the wells not being run at a near maximum level as the desperate for cash small natural gas exploration companies have to do to fight off bankruptcy.  We need to reform the way we price natural gas and get utilities and big users to get away from pricing natural gas based on the commodity markets often distorted low level of pricing that is currently below the cost of delivering natural gas due to speculators taking advantage of the deeply indebted natural gas companies often being required to hedge their production on the futures market with more hedging when prices ever creep up towards a profitable level.  We need utilities and natural gas power plants to be more focused on guaranteed availability of as much natural gas as needed so that in really cold times we have enough natural gas capacity to keep everybody warm unlike this spell where many shivered in houses where the pipes busted.  People have died because of the neglect to be prepared with extra natural gas capacity which affected heating but also importantly power generation.
 
America’s infatuation with pursuing the lowest cost even if it may not be reliable led Texas to a bad situation that has resulted in lots of damage and perhaps even loss of life.  Geothermal energy is the most reliable and longest lasting source of power but suffers from higher installed cost in many cases and also fails to satisfy investors and utilities that seek large power production instead of distributed power.   When you look at carbon emissions it is important to look at total lifetime emissions and in that case solar and wind with relatively short lives and lots of embedded carbon emissions really fail to be that desirable.  Geothermal electric power plants actually  make more energy as the temperature goes down as they are thermal processes that benefit from cooler condensation temperatures in the typical organic rankine cycle powerplant.  The best geothermal plants produce both electricity  and low temperature heat for heating needs or even to power a heat powered air conditioning unit.  This sharply boost overall efficiency. 
 
The other so called geothermal energy use is very sensible which is using the vast cool region of the near surface earth as a heat sink in summer to sharply reduce air conditioning bills and as an area for a electric heat pump to draw heat from in the winter very efficiently regardless of air temperature.  Texas wouldn’t have had the problem it had if we had gone to such systems that are very available yet require more investment than a typical air conditioner or heat pump.  Builders choose to build the cheapest way they can without regard to energy use or society having adequate power.  Geothermal heat pumps should be mandated for new buildings and retrofits encouraged for existing buildings.
 
We need to get real about providing stable secure essentials for all.