Abstract

A preliminary evaluation of the economic potential of micro-reactors for deployment in the heat and electricity markets in the state of Washington (WA) was performed.

To be economically attractive in the WA power market, the levelized cost of electricity (LCOE) for a micro-reactor ought to be significantly less than $100/MWhe. Current micro-reactor designs, entertained primarily for niche applications, do not meet those cost targets. The micro-reactor cost estimate analysis suggests that fuel cost is a prime cost driver. The micro-reactor cost estimate analysis suggests that micro-reactor designs with high-assay low-enriched uranium (HALEU) and/or expensive-to-fabricate fuel are not promising. Micro-reactor design efforts for attractive economics should focus on a core design with 5% low enriched uranium (LEU) fuel (preferably cheap uranium oxide) and relatively high specific power (>3 kW/kgHM). In particular, the high specific power entails either enhanced heat pipe technology or a move away from heat pipes altogether.

To be cost competitive in the heat markets in WA, the levelized cost of heat (LCOH) from a micro-reactor should be in the $30-50/MWht range, which appears to be within reach. micro-reactors could be co-located with major factories or industrial districts to provide process heat. We have reviewed a number of industrial sites in WA that could use heat from one or more micro-reactors. The sites were chosen based on the amount of (non-biogenic) CO2 emissions as reported in the WA Department of Ecology database. Only sites emitting 10,000 tons of CO2 per year (equivalent to an average of 6.3 MWt of heat) were considered. Only sites requiring heat at 600°C or less were considered. Many WA sites meet these criteria for heat supply by micro-reactors. The sites range from food processing plants to university campuses and airports, from district heating plants to gypsum product facilities, from paperboard mills to military bases, from chemicals production facilities to aircraft manufacturing factories. The total installed thermal capacity of these sites would be about 1,400 MWt, displacing some 2.2. million tons of CO2 per year. This installed capacity would require deployment of about 140 micro-reactors, which is a significant business opportunity. It is highly recommended that such opportunity be more thoroughly investigated by PNNL.

Assuming electricity and heat are available from a micro-reactor at $100/MWhe and $40/MWht, respective the cost of hydrogen produced by HTE coupled to a micro-reactor would be about $4.9/kg-H2, which is significantly higher than low-carbon alternatives such as steam methane reforming with CCS or wind. Therefore, micro-reactor-generated hydrogen does not appear to be particularly attractive, unless avoidance of the hydrogen storage and transportation infrastructure afforded by the micro-reactors more than compensates for its higher production cost.