DarthPuppy wrote:The impact of geographic location on solar panel output is well studied and documented.
And studies showing that during the summer with day-round sunlight they can produce well ignores the flip side of the year where they produce very little.
Anyone who reads this forum knows that I am a very big proponent of photovoltaics. That said, I will say the problems of effectively applying photovoltaics gets doubly harder as you move toward the poles: wintertime PV production drops while wintertime loads increase. Even at my location near Washington, DC, this makes running a typical home from solar power a significant challenge. Here are two examples:
Photovoltaics with net metering on my own home (39 degrees North latitude):
Electricity production in December and January is approximately 1/2 that of June and July. But electricity consumption in January and February is often 3X what I use in June and July due to the operation of a heat pump space heater. With the magic of net metering, I am able to size my photovoltaic system at 2X the summertime load in order to meet the total load of over 18 MWh/year. With that arrangement, I bank over 3 MWh during the summer months to be consumed during the wintertime. Since storage of that much electricity is not practical with current battery technology, I would need to triple the size if the PV array in order to operate the heat pump in the wintertime in an off-grid condition. My roof MAY be able to accommodate this much PV with current technology, but that would represent a significant waste, IMO.
An entirely off-grid home nearby (same 39 degrees North latitude):
This home is about the same size as mine and was designed from the ground up to be very thermally energy efficient and to store significant amounts of thermal energy in the concrete and stone slab in the basement (with R40 insulation below the slab). This home has both a PV array for electricity and a solar thermal array for heating both water and the basement slab. The photovoltaic array is about 1/3 the size of the array on my home and produces about 1/10 as much electricity as my system due to being battery-backed rather than grid-tied. The thermal array is 2/3 the area of the PV array, but it is 4X to 5X as efficient. Both arrays are mounted at steep angles to optimize wintertime production (and reduce summertime production). Both the electrical and the thermal systems are backed up with fossil-fuel-based systems. Home comfort is maintained in wintertime using a Swedish fireplace in the center of the home. Without it, temperatures get down to about 45 degree Fahrenheit in the worst weather conditions (with all systems functioning properly).
As you move toward the poles, both of these homes would require both larger systems AND better insulation. Annual solar production would drop (even though summertime production may increase). As you approach the Arctic Circle, the ability to provide either electricity OR heat from the sun in wintertime would approach zero. This is why countries such as Germany are pursuing using hydrogen for long-term storage of energy. Unfortunately, hydrogen storage increases the amount of electricity needed by 2X or 3X due to the significant losses. OTOH, the *theoretical* efficiency of electrolysis is 120%, meaning that in the future you may be able to consume heat during electrolysis in summertime. Likewise the theoretical efficiency of recombining hydrogen and oxygen is only 83%, meaning you WILL get heat from the fuel cell. Since you need heat in the wintertime, it can be a beneficial arrangement if the heat can be used. But we are not very close to these theoretical efficiencies today, so you get waste heat in both reactions.
DarthPuppy wrote:If I am correct on that point, then I'm correct regarding the resource allocation efficiency aspect, at least until such time as we are no longer resource constrained regarding solar panels and we can cheaply deploy them everywhere we desire power. I hope we get there sooner than later. Production is growing and costs are dropping, but we have a long ways to go yet.
Agreed. But I am hopeful that some day most of our needs can be met with solar power that is either used directly or stored thermally, in batteries or in something such as hydrogen. Today, I am in favor of preferring photovoltaics where they can be reasonably applied, even in places such as Canada and Germany, since they have long life and very low maintenance and environmental impact when compared with wind. This is particularly true when PV is placed on rooftops. Unfortunately, when utilities get involved, PV starts to have significant land-use impacts.
Germany is currently doing significant damage to their environment by leveling forests and building wind generators. Fortunately there is significant opposition rising from the citizens there to this type of destruction. My preference would be to use a much more measured approach which would allow the preservation of our environment while solar and other technologies mature. I am intrigued by kite-based wind generators
since they do not have the land impact of either wind turbines or utility-scale photovoltaics.