USGBC Overhauls Demand Response Pilot - in Response to Critics

I'm curious to know why the on-site generation option was eliminated. Load-shedding is preferable, of course. But even if you're still generating electricity on site, you're reducing utilities' need to build more power plants and related infrastructure. That has an inherent environmental value. Couldn't there be one point for on-site generation and two points for load shedding, or something like that?

The USGBC likely eliminated the on-site load shedding because of the extreme level of word interpretation that is causing changes to LEED documentation requirements that has been going on a long time, and is getting worse.

Having worked with the USGBC as a developer of LEED this is the likely thinking that happened.

On-site generation is assumed to be grid connected. If you grid connect then any site-generated energy is not used off-hours, and you are not actually shedding load. That is deemed as cheating LEED.

Yes, this type of thinking is odd. I do not believe in this type of word interpretation. But that is usually the type of reasoning used. It is not green reasoning. It is what I call word interpretation which, more often than not, is not green reasoning.

hi guys -

there are actually several reasons we've restricted the use of on-site generation but the principal reason is as you've already suggested Maura – turning something off is vastly preferable to turning something on.

in the most common generation as DR strategy i'm familiar with facilities folks crank up diesel gensets (which generally aren't grid connected) to avoid critical peak pricing/ratchet charges/time of use based rates, etc. obviously there are other technologies (fuel cells, fly wheels, pumped storage) but while utilities/grid operators don’t necessarily care how the load is alleviated, we are hoping to create incentive for the win-win associated with curtailment based DR.

switching one inefficient/dirty source (grid electricity) for another (diesel generator electricity) does have the advantages you mentioned relative to reducing the need build additional grid scale peaking infrastructure. that said, if you’re going to make that argument, it seems only fair that we consider the infrastructure and supply chains required to make it possible to run the genset as well. it’d take a bit to make an apples to apples comparison of the two scenarios but given the fact that we intuitively know that turning things off is 99 times out of a 100 a better bet, those resources seem better used elsewhere.
in the instances where the on-site generation resource is a renewable one, i find myself wondering why it’d ever not be utilized if it was possible to do so.

buildings are a huge untapped resource from a load shed/curtailment/DR perspective. on-site fossil based generation just kicks the can down the road.

Most LEED projects do not have diesel gensets, even though with on-site generation. The assumption appears to be that all on-site generation is dirty.

On-site generation uses 1/3rd the power of grid connected energy, based on how the energy analysis treats it: transmission line loses.

relative to curtailment/shed, all fossil fuel based on-site generation is dirty. it’s not an assumption.

transmission and distribution losses only account for about 10% of the total losses in the 3:1 site:source conversion you mention. the rest of the losses come from the thermal inefficiencies associated with the conversion of heat into electricity which exist for all fossil fuel based electric generation processes. delivered grid electricity is ~1.6 lb CO2/kwh. i have a study that states that CO2 emissions from diesel generators range 1.5-2.0 lb CO2/kwh so that seems like somewhat of a wash. i didn’t dig into it to find emissions factors of on-site natural gas or gasoline generators (i imagine gasoline is about the same as diesel and NAG is better than both) because the point of the credit is to take advantage of an inherently better opportunity.

your assertion that most leed buildings don’t have generators seems specious– i know many that do and with the leed portfolio shifting dramatically towards more existing building projects we’ll have many more. 99 times out of 100, it's better to curtail use than it is to generate. until we pick up the low hanging fruit, crediting generation based DR sends the wrong market signal.

What if you just limit all load shedding except solar PV. This is how PV is functioning on a national basis to reduce peak grid demand in Germany.
http://c1cleantechnicacom.wpengine.netdna-cdn.com/files/2012/06/Fraunhof...

Specious? 10%? No. One of 100 LEED project. One diesel gen for a cogen plant.

Site to source energy is 1 :3. It has been for a long time. Who convinced you it is 10%?

Hi Hernando,I'm not following your last note. I think everyone is in agreement that national avg site to source energy ratio is about 1:3. Brendan's point is that only about 10% of that differential is from transmission and distribution losses. Most of it is in the conversion of fossil fuel to electricity.Are you disagreeing with that? I'm confused.

right – what nadav said. table 2 of this paper - http://www.nrel.gov/docs/fy07osti/38617.pdf.

generation is generation - it's not preferable to curtailment.

as for solar - i guess we’ve been assuming that there are sufficient incentives to use the solar asset or any other on-site renewable generation. basically, if you've got solar and it's producing, why wouldn't it be employed? additionally, at least some of what the utilities are looking for relative to fast acting auto-DR in commercial buildings is load balancing help - the ability to compensate for temporary interruptions in the generation capacity of grid-scale renewable assets when it’s not sunny/windy. right now, at least some of those temporary interruptions are met with additional fossil generation. it’s not a direct correlation (because weather patterns are somewhat more micro-regional relative to sun/wind) but for the sake of argument, it seems somewhat risky to rely on on-site solar to compensate for an interruption of a grid scale solar generator.

Site to source is 1:3 per ASHRAE. Transmission loses are one component. There are other loses.

My point is the micro-generation is the preferable environmental solution to centralized grids.

The USGBC claimed that most projects are using diesel generators. That is not true. It would be a rare occurrence for LEED projects, but diesel generation appears to be the claim to toss on-site generation completely.

The only two cogen projects out of my 100 LEED projects were one small scale fuel cell, and one natural gas cogen plant. That had a diesel backup but only because the building operation was considered critical. Operations could not be shut down. Think about hospitals and internet/telecom services.

Reject something because the claim is the fuel is ugly is going to run you into trouble. Solar is considered superior but it is not high efficiency and the manufacturing is not exactly green. Natural gas is 1:1 with no lose in transmission but there are loses if you consider the extraction and processing of the gas.

I am certainly pushing for better green power generation. But, rather than toss self generation out because diesel fuel might be used base the credit given on pollutants types generated. That makes more sense and is already being done with refrigerants in LEED. In California, Title 24 projects are reporting CO2 generation based on fuel type and plants providing the fuels. The other "current" major power generation pollutions may be tracked later: Sulfur dioxide and nitrogen dioxide, with mercury ignored because there is nearly none generated in California (no coal power plants).

some on-site/micro generation may in fact be preferable to some large scale grid electricity but using less is far better than both.

be that as it may – it’s a fair point this credit could (maybe should) be based on CO2 emissions per kwh of electricity "generated". since utilities consider building scale DR to be functionally equivalent to turning on a generator, currently this credit requires you to generate electricity at 0 lbs/CO2-kwh. i'm not aware of any generation technology anywhere that delivers this level of performance (and DR will be a distant afterthought should such a technology emerge). curtailment is far superior to any existing on-site generation technology in all but very unique circumstances (and those circumstances have almost nothing to do with the on-site generation and almost everything to do with how the grid is operated).

i'm still hung up on this 1:1 natural gas thing. you cannot turn 1 therm of NAG into 29.3 kwh (1:1 energy conversion of NAG to electricity). the best gas turbine in the world is only 60% thermally efficient (if you use a combined cycle) and maybe 70% if you're doing really great cogen (which, while it does contribute lower grade heat, it doesn't contribute additional electricity to the mix). so under ideal conditions with no line losses, 1 therm of NAG is only going to get you 17.6 kwh of electricity. if I’m reading a table on the epa ghg inventory correctly, combusting 1 therm of NAG generates 11.0 lbs CO2 so we’re at .63 lbs CO2/kwh. pretty good, but not zero.

The 1:1 natural gas thing was probably a comparison of distributed generation vs central generation. The efficency of conversion will be the same regardless of where the power is made. The savings is in no transmission loss.

Life Cycle CO2 emissions based on technology type

Technology Description Estimate(g CO2/kWhe)
Wind 2.5 MW offshore 9
Hydroelectric 3.1 MW reservoir 10
Wind 1.5 MW onshore 10
Biogas Anaerobic digestion 11
Hydroelectric 300 kW run-of-river 13
Solar thermal 80 MW parabolic trough 13
Biomass various 14-35
Solar PV Polycrystaline silicon 32
Geothermal 80 MW hot dry rock 38
Nuclear various reactor types 66
Natural gas various combined cycle turbines 443
Diesel various generator and turbine types 778
Heavy oil various generator and turbine types 778
Coal various generator types with scrubbing 960
Coal various generator types without scrubbing 1050

Way back to Tristan's original post: I was approved to participate in this pilot credit and submitted my LEED documentation before the changes were made. I have to re-submit with additional documentation, including a more detailed description of design measures that permit demand response. I assume that the review team won't reject this credit now because we don't meet the criteria established later. (Whether those criteria are logical or not I will leave to the debaters here!) Is that correct?

Maura,
If you registered the project before the credit changed, you can still follow the credit requirements that were in effect at that time.

I'm finally getting a chance to attempt this credit and was excited to see the improvements. Onsite fossil fuel generators, in my experience, are not very efficient and that was always a means of shift that bothered me. Our project is fortunate to have Thermal Ice Storage capacity from the days of variable rates, and these provide a way to participate without using the generators. Interoperability with the grid is an exciting possibility here, as well as driving research into "dispatchable" renewables. The pilot credit process is working very well, by the way. Inspires innovation.