This thesis will also address how New York State's "50 by 30" initiative can shape the use of biomass energy in our area and make biomass a more attractive investment. Meanwhile, less urban areas of New York State are realizing how likely, even severe, power outages are.1 The combination of aging infrastructure and more erratic weather means that this problem will remain, if not worsen.
REVIEW OF LITERATURE
Combustion takes place at a later stage and provides heat for the gasification process to produce syngas: a mixture of hydrogen, carbon dioxide and carbon monoxide. A potential concern they noted with this approach is the additional land requirement for processing.9 This concern is mitigated by low land prices in Western New York.
METHODOLOGY
L OAD
Hornell, NY Overall Load
The national average electricity consumption, as shown in Figure 4 above, shows that household consumption is 37%, with industrial consumption accounting for 27% and commercial consumption for 35%. The summary in Table 1 above gives more precise figures for peak load and average load and provides average daily energy requirements and load factor.
Hornell, NY Residential Load
The seasonal profile in Figure 8 differs from Figure 6 in terms of total value and the total monthly minimums for Figure 8 are much closer to the average daily minimum, as can be seen by the whiskers almost touching the boxes. The overview in Table 2 above provides more specific figures for peak load and average load, as well as the average daily energy requirement and the load factor, the ratio between the average load and the peak load. Comparing the load factors between Tables 1 and 2, we can see the effect of the difference between Hornell's total daily power demand and residential power demand.
Alfred, NY Community Load
The seasonal profile indicates overall monthly minimum and maximum power demand, the months' average daily minimums and maximums, and the monthly overall average. The summary in Table 3 above provides more specific numbers for peak load and average load, as well as providing the average daily energy requirements and the load factor, which is the ratio of average over peak.
F EEDSTOCK
Dried Cow Manure
Regarding cow manure, we expand the local parameter to include all of Steuben County. For feedstock use, this will require drying, which applies a conversion rate of 0.52%, resulting in 1,800 dry tons of cow manure/year at $56/ton.12. The low conversion rate is mainly due to the high water content of the raw manure.
Decreasing this water content increases the amount of manure and other decaying food matter that can be put into an anaerobic digester, as shown in Figure 11 below, used for biogas production. This process can be further improved by incorporating a mixing mechanism to facilitate digestion, as well as by studying the bacterial ecosystem that has grown in the digester over time and optimizing that environment for quality methane production. As an anaerobic process, this production can be hindered by a sufficiently high presence of oxygen in the system, which can be inadvertently introduced by insufficient closure of the solvent or feedstock loading without protective measures.
Due to the highly variable temperatures experienced in Western New York, anaerobic digesters would benefit from primarily summer use or being built with insulation and/or heating elements. Depending on how the livestock is managed, there is also the potential to build close to the cows themselves to take advantage of body heat as well as any winter heating provided to the cows.
Wood (Oak)
This ensures a continuous flow of feedstock to the burner and allows for any final grading prior to combustion. The three components of combustion can be separated into raw material as fuel, furnace providing heat and finally air from a draft fan. The grit guard cleans the flue gas supply and the economizer captures residual heat and transfers it to the boiler feed water.
Wood biomass comes in many forms from unprocessed forest residues, sawmill and paper mill waste to discarded Christmas trees. This diversity in shape presents a challenge for modeling in that fuel data values can vary greatly between shapes. To reduce this variability, we used a common form of woody biomass in the area, namely oak trees, and modeled the system using its fuel data after charcoal production at 565℃.11.
In addition to increased efficiency and reduced transport, the use of carbon has the potential benefit of easier processing in the combustion phase. A common problem with wood biomass is its fibrous nature which creates flow problems such as bowing. A particular cause for concern in the biomass of oak forest residues that this system is using is the potential ecological consequences of harvesting.
Municipal Solid Waste (MSW)
B ATTERY AND C ONVERTER
The battery cost also includes the generic large, free converter that HOMER Pro™ offers as an option for sizing the battery without having to size the converter.18 The idealized battery unit is a 1 MWh Li-ion. Sizing of the battery system is a priority and the converter is, according to the note in the HOMER ProTM component properties, “intended to be as large as necessary to avoid bottlenecks in the conversion between AC and DC bus.” This method also takes into account losses due to inverter and rectifier efficiency, shown as 95% in Figure 14 above. This relationship with the battery system does mean that all inverter costs must be taken into account on the battery side.
Allowing the converter to operate in parallel with AC generators prevents excess electricity and capacity shortages on the same bus at the same time step. This and the high efficiency indicate that the converter modeled in the system is of high quality.
G ENERATOR
The generators will run in two different modes depending on the scenario being modelled, with or without CHP. Without cogeneration, the generators will run at 20% efficiency to reflect the biomass's power production capability. With cogeneration, the generators will run at 80% efficiency to reflect the higher overall biomass utilization with a cogeneration system.
E MISSIONS
RESULTS AND DISCUSSION
As shown in the table, the use of biomass in electricity production, with an efficiency of 20-25%, is not feasible even in the lowest load of the three, the Alfred community.
H ORNELL , NY O VERALL L OAD
H ORNELL , NY R ESIDENTIAL L OAD
Hornell Residential Load Subsidized
GHG capture comes at a high cost to the end user at $0.32/kWh, when current electricity prices are approximately $0.11/kWh. This change in the initial state requires a re-evaluation of the size of the generators as well as the number of batteries. One possible explanation for the increase in NPC and start-up capital is the salvage potential of higher capacity generators.
Providing a margin for overshoot, 10% as before, in the converter is a key component for system reliability as surges remain a major cause of failure. With this cost structure we see that oak energy production continues to be combined with cow manure in winter more severe than in summer. Comparing Table 18 with the unsubsidized use and energy production in Table 13, we see the use of oak biomass as the most affected.
This suggests that the reduction in oak energy production may be overcompensated by energy production from cows and municipal MSW. As shown in Table 19, the carbon sequestration value remains above 120,000 tons, similar to the unsubsidized system. This suggests that subsidizing the Hornell housing system by providing 0% loans does not provide an economic incentive based on net present costs to abandon energy production from cow manure, which provides an important source of carbon savings.
A LFRED , NY C OMMUNITY L OAD
Alfred Community Load Subsidized
As with Hornell Residential, energy costs for the system are too high compared to market rates. The same strategy for reducing consumer costs is applied by modeling the system with the option to take out subsidized loans, with an interest rate of 0% lower than the original 8%. Considering the 6.3 MW peak of the Alfred load, the basic search space used was the same as that for the unsubsidized model.
However, this led to three iterations where the model selected the highest possible generator size. This oversizing is most likely due to the combined effects of generator prices per kW decreases with the size and the subsidy used in the form of a 0% interest loan. As mentioned before, the current net cost of investment decreases as the initial capital and generator size increases.
Given the increase in initial capital between iterations 2 and 3 for the minimal reduction of net present cost of all subsequent data will be based on the second iteration. This number is based on the maximum rectifier output with a 10% buffer in the event of power surges. Due to the removal of the carbon capture provided by cow manure power generation, the subsidized Alfred Community model's reduced COE comes at a cost to the environment, as the system's CO2 emissions are not canceled out by anything, as shown in Table 29 above showed.
O VERALL C OMPARISON
SUMMARY AND CONCLUSIONS
A Western New York biomass microgrid requires CHP integration and the greater efficiency it allows to meet the power needs of Hornell Residential and the Alfred community. This indicates the need for additional income streams or other forms of assistance instead of or in addition to discount loans. The high average MSW production rate combined with its low cost makes it an ideal fuel.
Energy production from wood biomass and cow manure is in many cases considered secondary to MSW. This focus on electricity production limits the potential for biomass and the need for CHP integration. The similarity of biomass to traditional fuels, with the need for processing, transport and combustion, makes it subject to conversion losses and to the additional costs and emissions associated with transport and processing.
This manifests as a perception problem, putting biomass in stark contrast to its renewable counterparts, despite its calculated greenhouse gas reduction potential.
FUTURE WORK
